This disclosure relates generally to packaging of integrated circuits, and more particularly to a cleaning system and a package carrier for a semiconductor package.
When packaging a semiconductor chip after circuitry has been formed thereon, the interconnection between the circuitry on the chip and the input/output connecting pins on a package substrate may be implemented by Flip-Chip packaging technology. A Flip-Chip assembly includes a direct electric connection of a face down (that is, “flipped”) semiconductor chip onto a package substrate, such as a ceramic substrate, a circuit board, or a carrier using conductive bumps disposed on the semiconductor chip. Flip-Chip technology is quickly replacing older wire bonding technology that uses face up semiconductor chips with the wire connected to each pad on the semiconductor chips.
To package a semiconductor chip using Flip-Chip packaging technology, the semiconductor chip is flipped and positioned on a package substrate. Conductive bumps are reflown to form electric connections therebetween and provide limited mechanical mounting for the semiconductor chip and the package substrate. During the reflowing process, flux is used to facilitate the joining of the conductive bumps, bond pads on the semiconductor chip, and pads on the packaging substrate. Then, excessive flux residues are removed, and an underfilling adhesive, such as epoxy, is used to fill spaces between the semiconductor chip and the package substrate in order to provide even better mechanical interconnection between the semiconductor chip and the package substrate, increase the reliability and fatigue resistance of the package interconnections, and minimize uneven stress distribution caused by thermally induced strains due to the differences in coefficients of thermal expansion (CTE) between the semiconductor chip and package substrate.
However, if the spaces between the semiconductor chip and the package substrate were not filled properly, more stress would be carried by the relatively thin conductive bumps. As such, even a thin film of flux residue can cause premature delamination of a bonded surface, and result in failure in one or more of the interconnections. Therefore, it is important to remove flux residues from the Flip-Chip assembly by a flux cleaning process.